Pneumatic caisson.



No. 877,308. PATENTED JAN. 21, 1908.

0. 0. EDWARDS, JR. PNEUMATIC GAISSONJ APPLICATION FILED NOV.11,1905.

1m: NORRIS PETERS ca, wAsnmamn, n. c.

Y UNITED STATES PATENT omuon.

OLIVER CROMWELL EDWARDS, JR, OF RENSSELAER, NEW YORK.

PNEUMATIC CAISSON.

To all whom it may concern:

Be it known that I, OLIVER C. EDWARDS, Jr., a citizen of the United States, residing at Rensselaer, in the county of Rensselaer and State of New York, have invented certain new. and useful Improvements in Pneumatic Caissons and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relatesto improvements in pneumatic caissons, and one of the objects in view is the constructing of the parts for facilitating their employment as a permanent part of the completed structure.

With this and other objects in view, the invention comprises the combination of a concrete casing, a concreteroof spaced above the end of said casing and formed integral therewith, and a brace formed integral with the walls of said casing and arranged parallel to the roof.

The invention further comprises the combination with a composite casing, a com posite horizontal roof connecting the walls of said casing and arranged intermediate the length thereof, hollow shafts supported by and communicating through said roof, and strengthening means beneath said roof for stiffening the walls of said casing.

The invention still further comprises certain other novel constructions, combinations and arrangements of parts as Will be hereinafter more fully described and claimed.

In the accompanying drawings :Figure 1 represents a top plan view of a pneumatic caisson embodying the features of the present invention. Fig. 2 represents a side elevation thereof, parts being broken away for disclosing the interior structure, and parts being omitted for increasing the clearness of the disclosure. Fig. 3 represents a similar view of the end of the caisson. Fig. 4 represents a fragmentary top plan view of a portion of the caisson roof, a part of one side of the casing being shown in section. Fig. 5

represents a fragmentary detail vertical sectional view, the upper portion of which is taken on the plane of line 55 of Fig. 4, and the lower portion of which is taken on the plane of line 5-5 of Fig. 1, the plane of the section being indicated by line 55 of Fig. 2. Fig. 6 represents an enlarged, detail, fragmentary sectional view through a part of the Specification of Letters Patent.

Application filed November 11. 1905. $erial No. 286.924.

Patented Jan. 21, 1908.

roof showing the connection between one of the shafts and said roof. Fig. 7 represents a detail fragmentary sectional view through a part of the lower edge of the caisson casing illustrating a shoe applied thereto.

In the building of foundations in water for piers, retaining walls, dams andthe like, it has been common to employ a pneumatic caisson, and I have found it desirable to construct the same of considerable transverse area. Of course, the larger the caisson, the more material is required and, therefore, the more expensive is the production of the caisson. of a metallic or timber caisson I contemplate producing a caisson of a design which shall be susceptible of construction at consider ably less cost than required for producing a metallic or timber caisson, of a corresponding size, the larger the caisson the greater being the saving in expense, said new design being, of course, as efficient as the more expensive type.

I am aware that numerous forms of caissons have heretofore been made and that it has been proposed to make a caisson of con' crete, but I am unaware of any successful construction and use of such a caisson. As far as I am aware, it is new to construct a composite casing connected and strengthened by a horizontal composite roof and again connected and strengthened beneath the roof, in the working chamber of the easing, by suitable stiffening struts or bulkheads, said struts or bulk-heads being made of the same material as the casing and the roof.

Referring to the drawings, which show one illustrative embodiment of the present inven tion, 1 indicates the vertical wall of a surrounding casing which may be of any preferred size and shape, said casing being constructed of a composite of concrete and metallic bars, rods or old railroad rails, as indicated at 17. Cast integral with said casing is a roof 2 of the same material as the casing, the said roof being connected at all points of its edges with the walls of the casing, and being preferably considerably thicker than the thickness of the wall of the casing. The roof, at the point of its juncture with the casing throughout the length of its sides and ends, is formed with continuous, integral knee braces, as indicated at 3, for bracing and strengthening purposes. By continuous knee braces I mean knee braces which are integral Hence, in order to reduce the expense throughout their length, and which eXtend continuously and unbroken or substantially unbroken about the caisson inclosing wall.

The roof 2 is preferably arranged in a horizontal plane with respect to the vertical wall 1 and is disposed at the required distance above'the lower edge of the casing, for accommodating the workmen beneath the roof,

- and in order to facilitate the sinking of the caisson, the casing 1 has its lower portion tapered to a cutting edge. The longitudinal and transverse area of the working chamber beneath the roof is such that, owing to the thinness of the wall of the casing 1 beneath the roof (said wall being purposely made comparatively thin for facilitating sinking), unless guarded against, the said wall is liable to give way and precipitate sudden flooding of the working chamber. To avoid such flooding, I provide bulk-heads or strengthening struts or braces 4-4 formed integral with and connecting the opposite sides of the casing 1, the said strengthening struts being formed of the same material as the sides and roof.

The struts 44 are illustrated as arranged transversely of the working chamber and similar struts or braces 4 are shown as arranged longitudinally of the working chamber, said struts 4 being constructed of the same material. as the struts 4 and being formed integral with the under walls of the casing 1. Of course, the struts 4 may be omitted if desired. Above the roof 2 the walls of the casing 1 may be braced by suitably arranged. struts or braces 44, constructed of the same material as the casing and formed integral therewith. The struts 4", of course, serve to prevent inward giving of the walls of the casing 1 under the pressure of the surrounding water or earth.

The roof 2 may be penetrated by tubes or casings for accommodation of signal apparatus, etc., not illustrated, and in order to facilitate access to the working chamber beneath the roof by the workmen, a shaft 5 is arranged to communicate with said chamber, said shaft being provided with any ordinary form of air lock 6 near its upper end, such air lock not being illustrated. in detail as the same is, as far as the present invention is concerned, of any of the ordinary and well known types. I

As best seen in Fig. '6 the roof is formed with an opening or passage-way 8 of greater diameter than the diameter of the "shaft "5.

A plate 7, seen in detail in Fig. '6, is embedded in the material of the roof 2 and is formed with an annular aperture registering with the opening of the shaft 5, and of a diameter nearly equal to the internal diameter of said shaft, the shaft resting upon that portion of plate 7 projecting within the opening 8 in the material of roof 2. 'The weight of the shaft 5 is thus borne by the roof 2 through the plate 7 An angle plate 5 is preferably riveted or otherwise suitably secured to the lower end of the shaft 5, and has its horizontal web resting upon the plate 7, said web being detachably connected to the plate 7 by a suitable bolt or bolts 7. Owing to the difference in diameter between the shaft 5 and the opening 8, an annular clearance space 5 is left between the casing 5 and the roof 2, and, in operation, when the concrete is placed upon the roof for filling purposes, temporary steel frames are arranged about the shaft 5 for maintaining the clearance space'so that, when desired, the bolts 7 may be removed and the shaft 5 lifted out of the caisson. At the opposite sides of the shaft 5, or otherwise suitably positioned, are arranged spoil shafts 99 supported on plates 101O constructed and arranged similar to plate '7 and the construction and arrangement of attachin'" means being the same for shafts 9 as sha t 5. The shafts 9 are, of course, provided with any ordinary form of air locks 1111, not illustrated or described in detail, as said locksare, as far as this invention in concerned, of any ordinary and well known type, the said locks being provided for accommodating the removal of material. from the working chamber, and the introduction of material to said chamber without materially interfering with the degree of compressed air maintained in the working chamber beneath the roof.

The lower edge of thecasing 1 maybe made of a composite material, or, as seen in Fig. 7, a metallic shoe 12", formed from a channel iron, may be applied to the said edge for facilitating cutting through the substances through which the caisson is being sunk, said shoe being preferably retained in position by pins or bolts 12 embedded in the material of the caisson.

In the positioning of the caisson before operation, it is necessary, frequently, to float the same for some distance and the casing wall extending above the roof mate ri'ally aids in floating the same, as it tends to increase the water displacement without materially increasing the weight of the caisson. When floating a caisson it is necessary, of course, to close the shafts leading to the working chamber in order that the air may not escape therefrom, and, if desired, compressed air may be introduced into such chamber for preventing the admission of water to the chamber due to the weight of the caisson.

I find that in towing the caisson through shallow water the use of compressed air aids materially in increasing the buoyancy of the caisson, and obviates the necessity for auxiliary floats. The decided advantage gained by theuse of compressed air in the working chamber will be seen when it is considered that the Weight of concrete is more than twice the weight of water, and that, therefore, in order that the caisson may float of its own buoyancy more than twice as many cubic feet of water must be displaced by the caisson as the number of cubic feet of material of which the caisson is made. If an attempt is made to float the caisson without the use of compressed air and the coiferdam walls, or in other words, that portion of the casing which extends above the roof, projects to a suflicient height, the displacement will be sufficient for causing the caisson to float, but this will necessarily produce a very deep draft, and consequently a relatively great resistance to the forward travel of the caisson. The weight of the material of which the caisson is composed will not only resultin the displacement of twice its bulk of water,

but will result in admitting water to the working chamber by producing a compression of the air within the working chamber. By the introduction of air under sufficient pressure, the water so entering the working chamber may be ejected. In the use of a caisson with a working chamber 65 feet long and 20 feet wide, the ejection of all of the water from the working chamber by the supplying of compressed air thereto will result in an uplifting pressure exerted on the caisson amounting to approximately one hundred and forty tons, assuming the air pressure to be approximately one and onehalf pounds per square inch of transverse area of the working chamber. In other words, it is obvious that by the introduction of compressed air into a working chamber whose bottom is open, the displacement of the caisson is materially decreased without any substantial decrease in the actual weight of the caisson.

That portion of the casing 1 extending above the roof 2 may be continued upwardly as far as desired, but, by preference, I provide a cofferdam 13 connected with the upper edge of the said casing 1. The cofierdam 13 consists of a frame-work 14 suitably connected to the casing -1 (preferably by bolts 16 embedded in the wall of the casing and extending through portions of the framework) and a sheathing 15 arranged outside the frame-work 14. Of course, under some conditions, transverse and longitudinal struts or bulk-heads may be needed for sustaining the walls of the cofferdam 13 in osition and these may be employed or omitted in connection with the present invention, as may be found desirable.

The present improved caisson is adapted for use for facilitating excavation for foundations and is sunk in the usual manner by the removal of material from beneath the working chamber which permits the edges of the casing 1 to sink gradually into the material extending through the roof 2, and may be made to completely fill the working chamber without difficulty. When said chamber is filled the caisson is ready to receive whatever super-structure is intended to be built thereon.

What I claim is:

1.. In a caisson, the combination with an inclosing concrete casing, a roof formed integral with and connecting the walls of said casing, and bracing means formed integral with said walls and lying'parallel to one of the faces of said roof.

2. In a caisson, the combination of a vertical concrete casing, an integral horizontal roof of the same material, and a bracing strut formed integral with and connecting opposite sides of the wall of said casing and formed of the same material as said casing,

said strut being arranged beneath said roof.

3. In a caisson, the combination of a concrete casing, a horizontal roof of the same material, formed integral with the walls of said casing, and spaced above the lower end of the casing a distance sufficient for producing the working chamber, and bracing struts formed integral with the wall of said casing and extending across said working chamber.

4:. In a caisson, the combination of a concrete casing, a roof formed integral with said casing and spaced above the lower end there of a distance sufiicient for producing a working chamber, and horizontal braces formed integral with and connectim the walls of said casing within said chamber for preventing inward giving of said walls.

5. In a caisson, the combination with a concrete casing, a concrete roof spaced above the lower end of the saidcasing, and kneebraces connecting the walls of the caisson with the roof, said knee-braces being formed integral with such walls and roof.

6. In a caisson, the combination of a concrete casing, a concrete roof formed integral with the casing, said roof being formed with an aperture for permitting access to the space beneath the same, a plate embedded in said roof at the point of said aperture, and a hollow shaft resting upon said plate, the

' plate being formed with an apertureregistering with the bore of said shaft.

7. In a caisson, the combination with a casing, and a concrete roof supported thereby for producing a working chamber beneath the roof, said roof being formed with When the caisson has,

an aperture for permitting access to said working chamber, of a plate embedded in the material of said roof and formed with an aperture registering with the a erture in said roof, a portion of the materia of said plate extending into the aperture in said roof, and a shaft supported by that portion of said plate extending into the aperture of the roof.

8. In a caisson, the combination with a casing, of a concrete roof supported thereby and spaced from the lower end thereof a distance sufIicient for producing a working chamber, a plurality of apertures being formed in said roof, plates embedded in the material of said roof at the point of said apertures and projecting into the apertures, and shafts positioned on said plates for being supported thereby and for affording access to the working chamber.

9. In a caisson, the combination with a ver tical concrete casing, of a horizontal concrete roof connecting the walls of said casing and formed integral therewith, said roof being spaced above the lowerend of said casing a distance sufficient for producing a working chamber, means within said working chamber bracing the walls of the casing, shafts communicating through said roof with said working chamber, and a cofferdam mounted above the roof.

10. In a caisson, the combination of a concrete casing, a roof arranged intermediate the length thereof and formed integral therewith, and means for bracing the wall of said casing formed integral with said walls and arranged above said roof and parallel to the upper face thereof.

11. In a caisson, the combination of a concrete casing, a roof arranged intermediate the length thereof and formed integral therewith, bracing struts formed integral with and connecting the walls of said casing above .said roof, and means below the roof for bracing the walls of the casing, said bracing means being formed integral with the casing.

12. In a caisson, the combination of a casing, anda roof therefor formed with a ,trans verse opening, a shaft extending into said opening of less transverse area than that of said opening, whereby a clearance space is left between the shaft and the walls of the opening, and means supported by said roof and extending into the opening for sustaining said shaft. r

13. In a caisson, the combination with a casing, and aroof connecting the walls thereof and formed with a transverse opening, of a shaft extending into said opening, the opening being of sufficient size for producing a clearance space about said shaft, a plate ex? tending from said roof beneath said shaft for supporting the same, and means detachably connecting the shaft and the plate.

14E. In a caisson, the combination with a casing, and a roof connecting the walls there.-

of, said roof being formed with a transverse opening, a plate carried by said roof, and extending into said opening, a shaft resting upon said plate, an angle plate connected .to said shaft, and means detachably connecting said angle plate to the first-mentioned plate.

15. In a caisson, the combination with an inclosing casing, a horizontal roof formed in.- tegral therewith, and connecting the walls thereof, and braces formed integral with said walls and disposed for resisting external pres sure tending to press the walls of the casing inwardly, the said roof being designed to be weighted for sinking the caisson.

1 6. In a caisson, the combination with a concrete casing, ,a concrete roof spaced above the end .of said casing and formed integral with the casing, and continuous knee braces extending about the walls of the casing and about the edges of the roof and formed integral with the roof and casing.

. 17. In a caisson, the combination with an inclosing casing, a roof formed integral therewith, and connecting the walls thereof, and a brace formed integral with said walls and ar-.

the inclosure and connected with the walls of the casing, and an intersecting brace formed integral with the first mentioned brace at the point of intersection.

20. In a caisson, the combination with an inclosing casing, of a brace extending across the inclosure and connected with the walls of the casing, and a brace formed integral with the first mentioned brace and extending at an angle thereto.

In testimony whereof I affix my signature in presence of two witnesses.

OLIVER CROMWELL EDWARDS, JR.

Witnesses:

I'IAROLD S. BEERS, HUGH C. LEIBEE. 

